MCP23018/MCP23S18
1.6.1
I/O DIRECTION REGISTER
Controls the direction of the data I/O.
When a bit is set, the corresponding pin becomes an
input. When a bit is clear, the corresponding pin
becomes an output.
REGISTER 1-3:
IODIR – I/O DIRECTION REGISTER
R/W-1
IO7
R/W-1
IO6
R/W-1
IO5
R/W-1
IO4
R/W-1
IO3
R/W-1
IO2
R/W-1
IO1
R/W-1
IO0
bit 7
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
bit 7-0
IO7:IO0: Controls the direction of data I/O <7:0>
1= Pin is configured as an input.
0= Pin is configured as an output.
DS22103A-page 18
© 2008 Microchip Technology Inc.
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